Vane Pin Mount Anti-rotation Baffle Design
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Solution Overview
Problem
Implementing ceramic matrix composite (CMC) materials in gas turbine engine airfoils faces challenges due to the transfer of aerodynamic loads, which can cause rotation of support platforms, increasing stress on the airfoil fairing and potentially leading to undesired load distribution.
Innovation Solution
The vane arc segment design includes a spar with a clevis mount and a baffle that secures the support platform to the spar leg, using various joint configurations such as clevis mounts, weldments, and threads to prevent rotation of the support platform under aerodynamic loads, thereby distributing loads effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If CMC materials are used in airfoils for high temperature resistance, then temperature capability is improved, but load transfer and rotation stability deteriorate
Solution Approach 1:
A metallic baffle is introduced as an intermediary component between the CMC airfoil and the support platform. The baffle receives aerodynamic loads from the airfoil and transfers them to the support platform, preventing direct load transfer that would cause rotation. This mediator resolves the contradiction by enabling CMC temperature resistance while maintaining rotation stability through the baffle's load distribution mechanism.
Solution Approach 2:
The system employs a composite structure combining CMC airfoil material with metallic support components (spar, baffle, support platform). The CMC provides high-temperature resistance while the metallic components provide load-bearing and rotational stability. This multi-material composite approach allows each material to contribute its superior properties, resolving the contradiction between temperature capability and rotation stability.
2Adaptability or versatility
If support platform is allowed to rotate under aerodynamic loads, then load distribution flexibility is improved, but stress concentration on airfoil fairing increases
Solution Approach 1:
The metallic baffle acts as an intermediary load-distributing component between the airfoil fairing and support platform. It receives concentrated aerodynamic loads from the airfoil and distributes them across the support platform structure, preventing stress concentration on the airfoil fairing while maintaining controlled load distribution flexibility through the baffle's structural design.
Data Source
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AI summary
A vane arc segment (60) includes an airfoil and a spar (72) that has a spar platform (72a) adjacent a first fairing platform (66) of the airfoil fairing (62) and a spar leg (72b) that extends through a hollow airfoil section (64) of the airfoil fairing (62). An end portion (74) of the spar leg (72b) has a spar clevis mount (76). There is a support platform (78) adjacent the second fairing platform (68) that has first and second through-holes (80a/80b). The spar clevis mount (76) protrudes from the support platform (78). There is a spar pin (82) that extends through the spar clevis mount (76) and locks the support platform (78) to the spar leg (72b). A baffle (84) extends through the spar platform (72a), through the hollow airfoil section (64), and through the second through-hole (80b) of the support platform (78). The baffle (84) is secured in a joint (86) to the support platform (78) and thereby limits rotation of the support platform (78) about the spar pin (82).